Abstract: The effect of heat input on microstructure and mechanical property of pulsed plasma arc additive manufactured Inconel 718 superalloy samples were investigated. Five different heat inputs ranging from 1.08×106 J/m to 1.76×106 J/m were adop-ted by changing power and welding speed. The microstructure morphology, dendritic spacing, elemental segregation and interdendritic Laves phase were also studied by using optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that as the heat inputs increase, the microstructure morphology is changed from columnar dendrites to cellular dendrites, and dendritic spacing also increases from 6.34 μm to 9.09 μm. Consequently, elemental segregation of Nb and Mo are promoted so that the morphology of interdendritic Laves phase is changed from particles to chains, which leads to the decrease of microhardness.
1 Wang X K, Xing L, Xu W P, et al. Influence of process parameters on formation of friction stir additive manufacturing on aluminum alloy[J]. J Mater Eng,2015,43(5):8(in Chinese). 王忻凯, 邢丽, 徐卫平, 等. 工艺参数对铝合金搅拌摩擦增材制造成形的影响[J]. 材料工程,2015,43(5):8. 2 Thjis L, Verhaeghe F, Craeghs T, et al. A study of the microstructural evolution during selective laser melting of Ti-6Al-4V[J]. Acta Mater,2010,58(9):3303. 3 Ströβner J, Terock M, Glatzel U. Mechanical and microstructural investigation of nickel-based superalloy IN718 manufactured by selective laser melting (SLM)[J]. Adv Eng Mater,2015,17(8):1099. 4 Ram G D J, Reddy A V, Rao K P, et al. Microstructure and tensile properties of Inconel 718 pulsed Nd-YAG laser welds[J]. J Mater Process Technol,2005,167(1):73. 5 Richards N L, Chaturvedi M C. Effect of minor elements on wel-dability of nickel base superalloys[J]. Int Mater Rev,2000,45(3):109. 6 Jawwad A K A, Strangwood M, Davis C L. Microstructural modification in full penetration and partial penetration electron beam welds in INCONEL-718 (IN-718) and its effect on fatigue crack initiation[J]. Metall Mater Trans A,2005,36(5):1237. 7 Liu F, Lin X, Leng H, et al. Microstructural changes in a laser so-lid forming Inconel 718 superalloy thin wall in the deposition direction[J]. Opt Laser Technol,2013,45(2):330. 8 Chen Y, Zhang K, Huang J, et al. Characterization of heat affected zone liquation cracking in laser additive manufacturing of Inconel 718[J]. Mater Des,2016,90:586. 9 Trosch T, Ströβner J, Völkl R, et al. Microstructure and mechanical properties of selective laser melted Inconel 718 compared to for-ging and casting[J]. Mater Lett,2016,164:428. 10 Hinojos A, Mireles J, Reichardt A, et al. Joining of inconel 718 and 316 stainless steel using electron beam melting additive manufactu-ring technology[J]. Mater Des,2016,94:17. 11 Xu F J, Lv Y H, Xu B S, et al. Study on process of rapid prototyping based on pulsed plasma arc welding[J]. Mater Sci Technol,2012,20(3):89(in Chinese). 徐富家, 吕耀辉, 徐滨士,等. 基于脉冲等离子焊接快速成形工艺研究[J]. 材料科学与工艺,2012,20(3):89. 12 Kurz W, Fisher D J. Fundamentals of solidification[M]. Switzerland: Trans Tech Publications,1986. 13 Fu H, Geng X. High rate directional solidification and its application in single crystal superalloys[J]. Sci Technol Adv Mater,2001,2(1):197. 14 Manikandan S G K, Sivakumar D, Rao K P, et al. Microstructural characterization of liquid nitrogen cooled alloy 718 fusion zone[J]. J Mater Process Technol,2014,214(12):3141. 15 Mathiesen R H, Arnberg L, Bleuet P, et al. Crystal fragmentation and columnar-to-equiaxed transitions in Al-Cu studied by synchrotron X-ray video microscopy[J]. Metall Mater Trans A,2006,37(8):2515. 16 Wang H M, Zhang J H, Tang Y J, et al. Rapidly solidified MC carbide morphologies of a laser-glazed single-crystal nickel-base superalloy[J]. Mater Sci Eng A,1992,156(1):109. 17 Bouse G K, Mihalisin J R. 4-Metallurgy of investment cast superalloy components[M]∥Tien J K,Caulfield T.Superall Supercompos Superceram.San Diego:Academic Press,1989:99. 18 OdabaŞi A, Ünlü N, Göller G, et al. A study on laser beam welding (LBW) technique: Effect of heat input on the microstructural evolution of superalloy inconel 718[J]. Metall Mater Trans A,2010,41(9):2357.
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2017, Vol. 31 
